If you use [Fire-Watcher's Oath] then go into the Christmas Gnome transmorpher, you'll be made to a purple glowing gnome.
If you're a female, you'll also become a Male Gnome.
Addition: You can use [Fire-Watcher's Oath], then use [Super Simian Sphere](makes you to an ape with a bubble around you) and then jump into the gnome machine, you'll become a gnome with an extremly bright bubble around you.
Now, normally you wouldn't be able to mount up, nor jump on other peoples mounts.
This still wont let you mount up, but it'll make you be able to get on other peoples mounts.
Using the OATH; wont let you mount up alone, but if you use the oath, then the gnome machine, you can mount up, and all your mounts will have a very special glow.